Daily showers could make you ill, according to a study from the University of Colorado.

Researchers at the university analysed around 50 showerheads from nine cities, across seven states in the US, and found that 30% of the devices harboured significant levels of Mycobacterium avium (M. avium).

The M. avium is a pathogen linked to pulmonary disease that most often infects people with compromised immune systems but which can occasionally infect healthy people.

Researchers found that some M. avium and related pathogens were clumped together in slimy "biofilms" that clung to the inside of showerheads at more than 100 times the "background" levels of typical household water.

Richard Pace, lead researcher, said: "If you are getting a face full of water when you first turn your shower on, that means you are probably getting a particularly high load of Mycobacterium avium, which may not be too healthy."

Symptoms of pulmonary disease caused by M. avium can include tiredness, a persistent, dry cough, shortness of breath, and weakness. According to Pace, immune-compromised people like pregnant women, the elderly and those who are fighting off other diseases are more prone to experience such symptoms.